VistA (Enterprise Electronic Health Record)

OpenVistA and WorldVistA are two varieties of the largest and most robust CCHIT-approved electronic health record platform in the public domain. They are GPL licensed, are based on the US Veterans Administration health record system, and can be installed as an integrated database, server, and client system. See the detailed download and installation instructions for OpenVistA and WorldVistA, or visit Vistapedia for other instructions. Also see the Ultimate Server with OpenVistA EHR.

CAD

QCAD is a commercial CAD alternative to AutoCAD with a community open source edition. Install:

sudo apt-get install qcad

VariCAD is a commercial 3D CAD package for multiple platforms (including Linux). There is no open source or community version.

Mathematical solutions

Scilab, Octave, and Freemat are three open source solutions for solving complex numerical mathematical problems. Symbolic mathematical problems can be solved with Maxima and Mathomatic. All of these programs are included in the Ubuntu Universe repositories.

Octave

Gnu Octave is a free, open source (GPL licensed) platform for solving linear and non-linear equations, similar to (and mostly compatible with) Matlab. It interfaces well with Gnuplot. For troubleshooting tips, see this thread. Install:

sudo apt-get install octave3.0

Also recommended:

sudo apt-get install libatlas3gf-base gnuplot qtoctave

Note: QTOctave is a GUI for Gnuplot or Easyplot 1.1, and and the ATLAS library is an algebra-software-optimization set of utilities.

EasyPlot 1.1 is an alternative to GnuPlot, with a version that can be used with QTOctave. It must be installed from source.

An older GUI for Octave/Gnuplot is qgfe (available as the package qgfe).

Freemat

Freemat is a free, open source (GPL licensed) platform for solving linear and non-linear equations, similar to (and mostly compatible with) Matlab. Install from Add/Remove Programs (Edutainment) or

sudo apt-get install freemat

Maxima

Maxima is a free, open source (GPL licensed) computer algebra system (CAS) for doing symbolic mathematics. It can solve equations with many variables, simplify expressions, do calculus, and many other advanced operations. To install:

sudo apt-get install wxmaxima

To run, enter:

maxima

or select wxMaxima from the Applications/Science menu. wxMaxima is the standard Maxima GUI.

Mathomatic

Mathomatic is a free, open source (LGPL licensed) command-line computer algebra system for doing calculations and symbolic mathematics. It can automatically solve and simplify algebraic equations, do some calculus, and other simple but useful operations. To install:

sudo apt-get install mathomatic mathomatic-primes

To run, enter:

mathomatic

or select it from the Applications/Science menu.

Amateur Radio applications

Fldigi is a free, open-source (GPL) application for digital-mode amateur radio communications using a sound card. Enable "Community Maintained Software (universe)" in Software Sources; then install either from Add/Remove Programs under (Amateur Radio) or by typing

sudo apt-get install fldigi

Amateur Electronics

Arduino

Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. It's intended for artists, designers, and hobbyists interested in creating interactive objects or environments. See this tutorial.

LaTeX

LaTeX is a LaTeX is a free high-quality typesetting system for the production of technical and scientific documentation.

LyX

LyX is a WYSIWYG frontend and GUI interface useful in creating documents formatted for LaTeX. Install:

sudo apt-get install lyx

LaTeX Reference Managers

The standard LaTeX bibliography (BibTeX) tool can be manipulated with one of several tools: